Apparatus for casting



Nav. 1s, 1924.

O. P. LUETSCHER APPARATUS FOR CASTING 5 Sheets-Shet l Pneu Hay 5 1923 5Sheets-Sheet 2 O. P. LUETSCHER APPARATUS FOR CASTING r'ned May 5 IINVENTOR ./ww* 'M x MM,

Nov. 18, 1924 1,516,049

O. P. LUETSCHER APPARATUS FOR CASTING [med nay 5, 192:, 5 sheets-sheet 5Nov. 18, 1924.*

O. P. LUETSCHER APPARATUS FOR CASTING 5 shts-sheet 4 Flled Mayy 5, 1923M VENTOR Nov, 18, 1924.

O. P. LUETSCHER APPARATUS FOR CASTING 1923 5 Sheets-Sheet 5 Flieg may 5I V QlNVE-NTO'R Patented Nov. 18, 1924. Y

UNITED STATES omvnn r. Lun'rscnna, or rmsnunen, rnNNsrLvANu.

APPARATUS FOB CASTING.

Application led lay 5, 1,923. Serial No. 636,857.

T o all whom t may concern:

Be it known that I. OLIVER P. Lnn'rsonnn, a lcitizen of the UnitedStates, residing at Pittsburgh, county of Allegheny, and State ofPennsylvania, have invented a new and useful Improvement in Apparatusfor Castmg, of which the following is a full, clear,

and exact description.

The present invention relates broadly to metal casting, and moreparticiilarly to an improved apparatus for casting'non-terrous metals,such as zinc, although the applicability of certain features of theinvention to other uses will be apparent.

At the present time considerable ditliculty is encountered in thehandling of zinc throughout the entire process from melting to rolling.

It is well recognized that in accordance with present methods, there isa large waste due to imperfect sheets, crop ends and the like. Thisobjection could be materially counteracted by the production of largerslabs, as the amount of scrap, while remaining substantially the sameper slab, would then represent only a comparatively small percentage ofthe total amount of metal being handled, as compared to the presentcomparatively high percentage of waste. With the present systems,however, the uncontrolled cooling ot' the metal in the molds makes theproduction ot' larger slabs exceedingly diflicult on account of theexcessive shrinkage of the metal. This has' resulted in limiting thecommercial production of slabs that will be sound enough for good sheetsto about one hundred pounds.

In some cases, heavier slabs are cast, but they are only utilized tomake heavy zinc plate which does not require the high quality of metalthat must be used in the manufacture of thin gauge sheets.

In accordance with this invention, there is provided means foreiectively controlling the cooling of the metal in the molds, whereby abody of molten metal is always ,available to feed the shrinkage causedby cooling. This results in homogeneous slabs of any desired dimensionshaving Vsubstantially constant or uniform cross sectional areas.

These difficulties are Jfurther increased by the problems encountered inthe production and delivery to the molds of high quality metal. Theseproblems arise from contamination of the zinc during melting by reasonof oxidation, ash from the coal which enters the melting chamber, andiron from the ladles used for dipping.

I have also found that the production of large slabs is materiallyinfluenced, not only by the quality of the metal initially supplied Y tothe mold, and by the control of the rate of cooling of the suppliedmetal, but also by the temperature o the mold at the time it receivesits charge. 'It has heretofore been impossible to control the moldtemperature between the time of discharge of a formed slab and thereturn of the mold to the pouring station. Another object of thisinvention is to provide means whereby this mold temperature may beeectively controlled to produce the desired results.

This invention, by properly interrelating the various factorsinfluencing the formation of slabs, enables the production of largeslabs suitable for rolling thin gauge sheets. This makes it possible toradically change the methods now employed for rolling, so as to greatlyincrease the percentage of salable product produced from a given amountof molten metal.

In the accompanying drawings there are shown, for purposes ofillustration only,v

certain forms of apparatus suitable for carrying out the presentinvention, it being understood that the drawings do not deline thelimits o my invention, as changes may obviously be made therein withoutdeparting from the spirit of the invention 0r scope of the broaderclaims.

In the drawings:

Figure l is a side elevation of one form of mold supporting and movingapparatus,

Figure 2 is a view similar to Figure l, but on an enlarged scale,illustrating a portion of the right hand end of the apparatusillustrated in Figure 1,

Figure 3 is a transverse sectional view, on an enlarged scale, on theline III--III of Figure 2, looking in the direction of the arrows, oneform of furnace being illustrated in dotted lines,

Figure 4 is a detail View illustrating a portion of the mold movingapparatus,

Figure 5 is a view similar to Figure 4, but'showing the parts inslightly dilerent position, i

Figure 6 is a transverse sectional View 011 the line VI-VI of Figure 4,

Figure 7 is a top plan view illustrating thc' driving mechanism for themold carrying and moving apparatus, and

Figure 8 is a view similar`to Figure 3 illustrating a slightly modifiedembodiment of the invention.

In carrying outl the present invention it is desirable to replace thesomewhat cumbersome rotary tables heretofore used for carrying the moldswith an endless carrying chain 2 as cle-arly shown in Figures 1 and 2.This chain may comprise suitable side links carrying anti-frictionsupporting rolls 3 as clearly shown in Figure 3, and connected at theirends by transversely extending pins 4. These carrying chains are adaptedto directly carry the molds 5, in which the, slabs are formed,throughout a portion of the mold travel and to this end may bedimensioned and constructed with respect to the particular moldsto beused.

Conveniently, the carrying chains for each apparatus may be supported ateach end by angular sprockets 6 around which they pass. These sprocketsat atlleast one end of the apparatus may be mounted upon a shaft 7adapted to be positively driven by a motor 8 through a. suitable trainof gears as clearly shown in Figure 7. The gear train will obviouslybear such ratio to the motor speed that the carrying chains will bemoved to deliver the molds continuously as required.

In order to permit the replacement of molds as may be necessary, themolds are preferably loosely carried by the chains 2. For this purposethe molds may be provided with downwardly extending projections S)adapted to extend over the pins 4 to provide driving engagement betweenthe chains and the molds. During such portion o-f the time as the moldsare supported on the upper run of the chains, they are held in positionby gravity. During the return movement of the molds, they may rest onsupporting channels 10. Curved guards 11 may cooperate with the channelsl0 at each en d thereof to insure the passage of the moldsto and fromthese channels.

During the travel of the chains, the molds are adapted to besuccessively filled with molten metal, such as zinc, then allowed tocool at a rate which is regulated in a novel manner whereby theresulting slabs are of greater uniformity, and are then discharged.

Referring more particularly toFigures 1 and 2 of the drawings, the moldsare shown as traveling from the right hand end of the apparatus to theleft hand end thereof. After passing over the driving sprockets 6 thecarr ing chains incline downwardly over a suitable guide 12. As thecarrying chains move downwardly, they force the molds onto spaced slides13 along a portion of which the molds are positively pushed by thefollowing molds. When a mold reaches the station A, shown in detail inFigures 4 and 5, it is adapted to be positively pushed ahead by aspecial mold pusher mechanism. T iis mechanlsm comprises a shaft 14carrying upwardly and inwardly extending levers 15 pivotally connectedat their upper ends to links 16. These links are in turn pivotallyconnected to lugs 17 extending downwardly from slides 18 mounted in theframe 19 of the apparatus. Carried by the slides 18 and projectingupwardly therefrom are pivoted pushers 20 arran ed in sets spacedlongitudinally of the sli es. The

spacing of the pushers is such that adjacent i pushers will cooperatewith adjacent or Successive molds for effecting simultaneous movementthereof. The shaft 14 is adapted to be rocked to effect movement of themold pushers from the position shown in Figure 4 to that shown in Figure5 bymeans of a crank arm 21 secured to one end thereof and in turnconnected by a pitman 22 to an eccentric This eccentric may be rotatedin timed relation to the movement of the carriers by means of a motor24. It will be understood that the motors 8 and 24 may either besynchronous motors, or may be automatically controlled in such mannerthat rotation thereof may be maintained in substantial synchronism. Eachmovement of the pushers from the position shown in Figure 4 to that ofFigure 5 will be effective for moving a mold from station A to Sta-ltion B at which the molds are adapted to be filled with molten metal.During the return movement of the pushers 20, they`are permitted to passfreely under the molds due to their pivotal mountings andcounterweighted end ortions 25.

At station which may be considered as the pouring point, the molds maybe supported in any desired manner. Preferably, however, they aredirectly carried on suitable supports 26 extending upwardly from a scalebeam 27 connected in any well known manner to an indicator 28, wherebyan operative may readily determine when the proper amount of metal hasbeen run into the mold. At such time the supply of molten metal will becut off to permit the removal of the filled mold and the delivery of anempty mold to the station B. This will be automatically accomplished bythe movement of the mold pushers 'as before described. This movementcauses the front pushers 20 to engage the filled mold at the station Bwhile the rear pushers engage an empty mold at the station A. Themovement thereof to the left will then be eifective for moving thefilled mold from the station B to station C while moving an empty moldfrom station A to station B as before set forth. At station C the filledmolds are received by a counterwei hted platform 29 vertically movablethrong the frame 19 and carried by one end of a counterweighted lever 30having a pivotal mounting 31. This platform 29 is normally held in theposition shown in Figure 4 to receive a filled mold by the action of thecounterweight- 32 as well yas the action of a catch 33 pivotally carriedby the frame 19. When the movement of a filled mold from the station Btostation C has been completed, a lug 34 on the mold pushing mechanismengages the tail of the catch 33, as clearly shown in Figure 5, andreleases the same from engagement with the platform. The weight of thefilled mold causes the platform to descend to the position shown inFigure 5. The platform is temporarily positively held in this positionby a swinging latch 35, carriedby the frame 19, which swings over thepin 36 of the lever 30.

In order to positively move the filled mold from the position above theplatform 29, to permit the platform to again return to mold receivingposition, .it is necessary to provide supplemental mold movingmechanism. This supplemental mechanism may conveniently compriselongitudinally extending spaced screws 37 supported at spaced pointsthroughout their length in brackets 38 carried by the frame 19. Adjacentthe right hand end of the apparatus, the screws are connected to driveshafts 39 carrying bevel gears 40. These bevel gears are simultaneouslyrotated in unison by bevel driving pinions 41 secured to a drive shaft42 having an operative driving connection with the motor 8, as shown inFigure 7.

Carried by each of the molds are threaded projections 43 constituting ineffect halfnuts. Upon the lowering movement of the platform 29 as beforedescribed, the halfnuts 43 Acome into engagement with the continuouslyrotating screws 37 and are thereby moved to the left, as viewed in thedrawings. This movement brings the leading edge of the mold, asindicated in dotted lines in Figure 5, into engagement with the tail ofthe catch 35 thereby moving'it to a position to release the pin 36, andpermit the counterweight 32 to return the platform to the position shownin Figure 4 ready for the reception o-f the neXt mold. This operation isrepeated each time a filled mold is delivered to the platform.

The screws 37 may be of any desired length in accordance with thecapacity of the particular apparatus and in accordance with the lengthof time which it is desired to keep the material in the molds beforedischarge thereof. As clearly shown in Figure 3 they may be located onopposite sides of a trough 44 adapted to contain a supply `of coolingwater which may be continuously delivered thereto in any manner. Themolds may each be provided with a series of depending fingers or flanges45 adapted to enter the water in the trough and thereby assist incooling the metal in the mold during its travel thro-ugh the apparatus.This cooling, which has heretofore been uncontrolled, produces ashrinkage of the metal. Duetto the factthat the upper surface of themetal has heretofore been exposed to the cooling action of 'the air, themetal has been caused to sink down-A wardly and frequently crack,thereby producing an imperfect slab. In accordancel with this inventionthere is preferably provided means for controlling the rate of heatdissipation or cooling of the upper body of molten metal inthe molds,either by heat insulating the same or by positively supplying additionalheat thereto. This means, as shown in Figure 1, may comprise a hood 47which may be of any suitable material, and which may if desired havelocated therein suitable heaters or burners 48. This hood is of suchwidth as to completely enclose the molds as they are `received aftertravel from the platform 29 and may be of a length such that the desiredrate of cooling may be effectively con trolled. In this manner it ispossible to keep the upper portion of the metal in the molds in liquidform whereby it is available to feed the shrinkage and thereby insurethe production of a solid slab of uniform composition.

The carrying chains, which after'leaving the inclined guides 12, mayextend downwardly below the screws 37 where they are supported on guides49. After leaving the guides 49 they travel upwardly to the sprockets 6at the left hand end of the machine. During this movement, the pins 4,or the rollers 3 thereon, engage the leading lugs 9 and lift the moldhaving a chilled slab therein from the end of the trough 44. These moldsare then carried to the station lD, shown in Figure 1, at which theslabs fall outwardly, under the influence of gravity, onto supportingarms 50. These supporting arms 50 are preferably pivotally mounted andprovided with suitable counterweights 51 whereby the weight of adischarged slab may swing them into the dotte'dlineposition` shown inFigure 1. This permits the slab to be automatically discharged anddelivered to any desired point from which they may be carried to anannealing furnace to prepare -them for rollin@ as is customary in theart.

uring vthe return travel of the molds, while supported by the channels10, they may be shielded in any desired manner to prevent furthercooling thereof, or a sep arate hood 52 similar to the hood 47 and havinsuitable heating means 53, may be provided. In this manner theobjectionable cooling of the molds which has heretofore occurred betweenthe point of discharge and the return to the pouring point is obviated,

- it being possible to kee the molds from 1oslustratet aslightlymodified form of the invention in which parts corresponding to partsalready described are designated by the same reference characters havinga prime suixed thereto. with this construction the screws 37 areindicated as being of greater length than those illustrated in Figures land Q of thedraivings, as they are preferably long enough to extendbeyond station or the pouring station which is the positionsillustratedin Figure 8. In order to prevent the continuous travel of the moldsduring the delivery of the metal thereto, it is obviously necessary toraise the same out of engagement with these screws. For this purpose thescale beam 27 may carry a motor adapted to drive a transverselyextending shaft 5G having a worm and -worm wheel connection (not shown)with lifting rods 57. lVhen the motor is operated in one direction theliftinor rods 57 win be raised t@ ua the molti which is in pouringposition into the posi tion indicated in dotted `lines in Figure 8.After the mold has received the desired amount of metal, the motor* maybe driven in the reverse direction to again lower the half-nuts 43 ontothe screws 37. This construction is advantageous for certain purposesfor the reason that it is possible to raise the mold into a osition moreclosely adjacent the point of c ischarge of the molten metal and therebyprevent cooling of the metal to an undesirable extent and materiallyreduce oxidation.

In this figure, there are illustrated carrying chains 2 of a slightlymodified construction, and the molds are each indicated as provided withlaterally extending projections 9 adapted tog engage suitable pockets 58carried by the side links. lar construction of the molds and chains may,however, be changed in accordance with the requirements of theparticular installation for which the equipment is designed, it beingonly essential that the molds be readily disengageable from the carr ingchains and that the chains be capable of impart-ing the desired movementto the molds.

For the purpose of maintaining the desired level of cooling-water in thetrough MJ, the water may be delivered thereto through an inletconnection 59. The trough is in turn connected to an outlet-connection60 having an intermediate overflow device 61. lVith this construction,the rate of cooling of the lower portion of the molds may be varied bysuitably changing the volume of How of cooling water. l

While it will be apparent that the mol- The particuten metal may bedelivered to the molds in any desired manner, the full advantages of thepresent invention are obtained. where the molten metal is produced andmaintained under conditions in which contamination by reason ofoxidation, ash, or iron from' dipping ladles is prevented. For thispurpose there is preferably employed an electric furnace of the typeillustrated in Figures 3 and 8.` This furnace comprises suitablerefractory walls 62 carried by a base pivotally mounted on trunnions 63.The top of the furnace is preferably closed at all times by a cover 64through which one or more temperature controlling pyrometer couples 65may extend, as desired. The furnace may be heated by suitable means suchas resistors R. By reason of this construction it is possible tomaintain a n0noxidizing atmosphere within the furnace at all times.Furthermore, by reason of the use of electricity, contamination from ashis prevented.

This furnace is also preferably of the direct pour type having an outletopening 66 controlled by a vertically movable plug 67 of a type similarto that used in ordinary steel ladle work. This plug may be operativelyconnected to an operating lever 68 whereby when the scale shows that theproper amount of material has been delivered to the mold, the operativema move the plug to cutofll the further flow of metal.

Adjacent the outlet G6, there may be provided a boot or spout 69 adaptedto receive the molten metal and transfer it to the mold. This boot notonly minimizes splashing but restricts the period of contact with theair and the consequent cooling and oxidation. If desired, there may beprovided a burner 70 for maintaining the metal in molten condition.

This furnace may be constructed so that during the normal operationthereof it is adapted to occupy an inclined position as clearly shown inFigure 8. With such a construction, in the event of injury to the plugor outlet, the furnace may be tilted in the opposite direction toentirely uncover the outlet and thereby permit repair thereof withoutshutting down the operation of the entire furnace or withdrawing all ofthe molten metal therefrom.

A furnace of this type has many advantages, among which may be mentionedits comparatively small capacity, whereby the investment represented bymolten metal is decreased, its cleanliness of operation wherebyvcontamination by foreign material is prevented, its closed conditionmaterially restricting oxidation, and its direct pour whereby ladling ismade unnecessary. This admirably cooperates with the improved moldhandling apparatus as it delivers a higher quality metal to the moldsand thereby contributes an improved factor involved in thc production oflarge slabs.

- By the present invention there is provided means for easilycontrolling the temperature atwhich the molds are brought to the pouringpoint. After the desired amount of metal has been delivered to themolds` the rapidity of cooling ofthe metal in the molds may beaccurately controlled to feed the Kshrinkage as required. This isaccomplished by either varying the amount of cooling water, varying theamountof heat supplied to the upper portions of the molds or controllingthe rate ofv heat dissipation, or by a suitable interrelation of thesefactors.

The advantages of the mold handling ap-A paratus arise from the ease ofcontrol of the molds, their delivery automatically as required, and thecontrol in the rante of cooling whereby the shrinkage caused by thecooling of the metal in the lower portion of the mold may be fed by themolten metal in the upper portion thereof.

Still further advantages arise from the provision of a mold handlingapparatus 1n which, after the discharge of the slabs from the molds, themolds may be prevented from further cooling, or may 'be preheated asclesired.

Still further advantages arise from the provision of a compact moldhandling apparatus of large capacity so constructed that molds ofdifferent sizes may be substituted, or repairs made, kas may benecessary.

I claim:

1. In a casting apparatus, a scale, means for supporting a mold thereon,means fordelivering molten metal thereto, and means for removing afilled mold from the scale beam, substantially as described.

2. In a casting apparatus, a trough containing a cooling medium, andmeans on opposite sides of said trough for supporting a mold and movingthe same through the trough, substantially as described.

3. In a casting apparatus, an endless conveyor, a plurality of moldsdetachably carried thereby, said endless conveyor being adapted todeliver the molds successively to a charging station and a dischargingstation, and means intermediate said stations for cooling the bottoms ofthe molds and for controlling the rate of cooling of the metal in theupper portions thereof, substantially as described.

4. In a casting apparatus, an endless conveyor. a plurality of moldsdetachably carried thereby, said endless conveyor being adapted todeliver the molds successively to a charging station and a dischargingstation, and means intermediate said stations for addin heat to aportion of a charged mold and or cooling another portion thereof,substantially as described.

5. In a casting apparatus, an endless conveyor. a plurality of moldsdetachably carried thereby, said endless conveyor being adapted todeliver the molds successively to a charging station and a dischargingstation, and a heat retaining hood arranged to enclose the molds duringa portion of their travel from one of said stations to the other,substantially as described.

6. In a mold handling apparatus. a screw,`

means for rotating the same, a mold adapted to be moved by said screw.means to move the mold to a charging station, and means for delivering acharged mold to a position for cooperation withy said screw.substantially as described.

7. In a mold handling apparatus, a trough adapted to contain a coolingmedium, a screw at one side of said trough, a mold having a portionprojecting into said trough and a portion engaging said screw wherebythe mold is moved through the trough, `and means cooperating with themold during its travel through the trough for controlling thedissipation of heat therefrom, substantially as described.

8. In a mold handling apparatus, a trough adapted to contain a coolingmedium. a. screw at one side of said trough, a mold having ya portionprojecting into said trough and a portion engaging said screw wherebythe mold is moved through the trough, and means cooperating with a moldduring its travel through the trough for adding heat to a portion of themetal therein` substantially as described.

9. In a moldhandling apparatus, a trough, a screw on each side thereof,means for rotating said screws, a plurality of molds having means forengagement with said screws, means for delivering said moldssuccessively into position to be engaged by said screws, and means forcharging said molds during their delivery to screw-engaging position.substantially as described.

10. In a mold handling apparatus, a mold, ascrew` for moving said moldthrough -a portion of its travel, an endless carrier for moving itthrough another portion of its travel, and a counterweighted transferdevice between said screw and said endless carrier, substantially asdescribed.

11. In a mold handling apparatus, a mold, a screw for moving said moldthrough a portion of its travel, an endless carrier for moving itthrough another portion of its travel, and a vertically movable transferdevice between said screw and said endless carrier. substantially asdescribed.

12. In a mold handling apparatus, means for successively moving aplurality of molds from a charging station to a discharging station andthen returning the same to the charging station. and heat retaininghoods intermediate both of said stations, substantially as described.

13. In a mold handling apparatus, means for successively moving aplurality of molds from a chargingstation to a discharging station andthen returning the same to thel charging station, and a heat retaininghood through Which the molds pass in traveling from' the dischargingstation to the lcharging station, substantially as described.

14. In a mold handling apparatus, a charging station, means fordelivering molds successively from the charging station to thedisch-arging station, and means intermediate said stations for retardingthe dissipation of heat from a. portion of a charged mold, substantiallyas described.

15. In a mold handling apparatus, a charging station, a 1 dischargingstation, means for delivering molds vsuccessively from the chargingstation to the discharging station, means intermediate said stations forretarding the dissipation of heat zfrom a portion of a charged mold, and

means intermediate said stations for artificially chilling anotherportion of a charged mold, substantially as described.

16. In a mold handling apparatus, a charging station, a dischargingstation, means or successively moving molds from the charging station tothe discharging station, and means intermediate said staa. dischargingstation,

tions for adding heat to a portion' of a charged mold during its passagefrom one station to the other, substantially as described.

17. In a casting apparatus, mold support. ing means, and means formelting metal in a non-oxidizing atmosphere and flowing the same directltherefrom into a mold ,su ported by said mold supporting means, sustantially as described.

18. In a casting apparatus, means for carrying a plurality of molds in`succession past a charging station, means at said charging station formelting metal in a non-oxidizing atmosphere and charging the moldstherewith Ias they are brought to said station, and means adjacent saidstation for cooling a portion of each charged mold, substantially asdescribed.

19. InVv a casting apparatus, means for moving a yplurality of molds insuccession from a charging station 'to a discharging station, means atthe charging station for melting metal in a non-oxidizing atmosphere andcharging the molds therewith, and means intermedi-ate said stations forcontrolling the rate of cooling of the metal in the upper portions'ofthe molds, substantially as described.

In testimony whereof I have hereunto set my hand.

OLIVER P. LUETS'OHER.

